How did the myth of Jesus' resurrection originate?

[xpastor]

This problem for the Jewish priest could have been easily solved. All they had to do is open the grave and show Jesus was still in the grave, why didn't they should be the question nonbelievers ask themselves, why didn't they.

You're making a lot of assumptions in a modernistic vein.

First, that Jesus was in a well-identified grave, maybe with an inscription like this:

Jesus H. Christ
4 BC - 30 AD
R.I.P.

Second, that people would know what he looked like.

Third, that decomposition would not have changed his appearance beyond recognition.